1. Field of the Invention
The present invention relates generally to heat exchangers and, more specifically, to a manifold and/or refrigerant plate and method of making same for a heat exchanger in a motor vehicle.
2. Description of the Related Art
It is known to provide plates for a heat exchanger such as an evaporator in a motor vehicle. Typically, opposed plates carry a first fluid medium in contact with an interior thereof while a second fluid medium contacts an exterior thereof. Typically, the first fluid medium is a refrigerant and the second fluid medium is air. Where a temperature difference exists between the first and second fluid mediums, heat will be transferred between the two via heat conductive walls of the plates.
It is also known to provide beaded plates for a heat exchanger in which beads define a plurality of passageways between the plates for movement of a fluid therethrough to increase the surface area of conductive material available for heat transfer and to cause turbulence of the fluid carried in a channel between the plates. An example of such a heat exchanger is disclosed in U.S. Pat. No. 4,600,053. In this patent, each of the plates has a plurality of beads formed thereon with one plate having one distinct variety of beads and the other plate having another distinct variety of beads. The beads of the plates contact each other and are bonded together to force fluid to flow therearound.
Performance of heat exchanger cores such as evaporator cores has been directly linked to refrigerant flow distribution through the core. This includes the flow distribution in a flow header or tank and a tube or plate areas. It is known that an effective way of generating a more uniform flow through the channel is by using a large plenum area upstream of the channel. Therefore, there is a need in the art to enhance the thermal performance in the heat exchanger core through the enhancement of coolant flow distribution inside the core.
The effectiveness of the refrigerant flow distribution through the core is measured by the thermal performance, refrigerant pressure drop, and infrared thermal image of the core skin temperature. Non-uniform distribution of flow starts at the flow header or tank area of the core.
The refrigerant pressure drop inside the core is controlled by several factors: heat transfer from the core to the air; flow restriction inside the core; non-uniform distribution of the refrigerant inside the core; and the change of phase from liquid to vapor because vapor has a higher pressure drop. The pressure drop can increase significantly when any combination or all of these factors are taking place together. Therefore, there is a need in the art to provide a heat exchanger with increased core thermal capacity, minimum increase in refrigerant pressure drop and minimum air temperature non-uniformity.
Therefore, it is desirable to restrict the flow in a back side of a manifold and/or refrigerant plate to improve refrigerant flow distribution inside a heat exchanger. It is also desirable to provide a manifold and/or refrigerant plate for a heat exchanger having a restriction to refrigerant in the heat exchanger. It is further desirable to provide a manifold and/or refrigerant plate having a restriction for a heat exchanger that improves refrigerant flow distribution inside the heat exchanger.
Accordingly, the present invention is a heat exchanger including a plate extending longitudinally and a plurality of plurality of apertures forming a fluid inlet and a fluid outlet extending through the plate. The heat exchanger also includes a mechanism forming a restriction to fluid flow through either one of the fluid inlet or the fluid outlet.
Also, the present invention is a method of making a heat exchanger. The method includes the steps of providing a plate extending longitudinally and forming a plurality of apertures in the plate and forming a fluid inlet and a fluid outlet. The method also includes the step of forming a restriction to fluid flow through either one of the fluid inlet or the fluid outlet.
One advantage of the present invention is that a heat exchanger such as an evaporator is provided for use in a motor vehicle. Another advantage of the present invention is that the heat exchanger has a restriction in a back side of a manifold and/or refrigerant plate that is either cross-shaped, round or multiple apertures. Yet another advantage of the present invention is that the heat exchanger has a restriction that improves the refrigerant flow distribution inside the heat exchanger by restricting the flow in the flow header or tank. Still another advantage of the present invention is that the heat exchanger has improved flow distribution using multiple apertures for a plate-fin heat exchanger such as an evaporator. A further advantage of the present invention is that the heat exchanger improves heat transfer by improving refrigerant flow distribution and enhancing flow mixing inside the flow header or tank. Yet a further advantage of the present invention is that a method of making the heat exchanger is provided with either a cross-shaped, round aperture or multiple aperture restriction in the back side thereof.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood after reading the subsequent description taken in conjunction with the accompanying drawings.